The invention relates to a method of determining the speed of a runner, walker or another moving and living object by a measuring arrangement, the method comprising measuring in the actual determination of speed during use at least one measurement variable which is directly or indirectly related to the object""s stepping and dependent on the speed of movement of the moving and living object.
The invention relates to a method of determining the speed of a runner, walker or another moving and living object by a measuring arrangement, the method comprising measuring in the actual determination of speed during use at least one measurement variable which is directly or indirectly related to the object""s stepping and dependent on the speed of movement of the moving and living object.
The invention also relates to a measuring arrangement for determining the speed of a runner, walker or another moving and living object, the measuring arrangement comprising a sensor for measuring at least one measurement variable, which is directly or indirectly related to the object""s stepping and dependent on the speed of movement of the moving and living object.
The invention also relates to a measuring arrangement for determining the speed of a runner, walker or another moving and living object, the measuring arrangement comprising a sensor for measuring at least one measurement variable, which is directly or indirectly related to the object""s stepping of the object and dependent on the speed of movement of the moving and living object.
There are several different prior art methods and measuring arrangements for measuring a person""s speed.
One known method is to use a pedometer, i.e. a meter of the number of steps, into which the step size is fed as additional data, and thus the distance traveled is found out by multiplication. The speed is obtained by dividing the distance traveled by the measured elapsed time. A problem related to this is, however, that changes in the step length due to changes in the speed cannot be eliminated or taken into account. Furthermore, it is difficult to measure the step length accurately.
Another known method is to use the Doppler device, which is based on the transmission of radar waves and detection of the radar waves reflected from the object. This method is, however, expensive and has high power consumption. It is also sensitive to changes in the terrain and to interference sources in the vicinity.
A further method is to attach an acceleration sensor to the leg because the speed can be determined from the signal sent by the acceleration sensor by means of integration. Attachment of the acceleration sensor to the leg constitutes a problem because the coordinates of the acceleration sensor rotate resulting from the fact that the leg is not at a standard angle but the leg and thus also the acceleration sensor rotate. Only measuring rotation of the leg and the acceleration sensor, which would be very difficult in practice, could solve the problem.
In addition, it is known to use the acceleration sensor on the hips in combination with a neural network. The problem related to this method is that placing of the sensor exactly in the same spot as before in forthcoming measurements is difficult, and thus the acceleration signal obtained form the sensor will differ from that of the other measurements.
U.S. Pat. No. 5,891,042 disclose a pedometer provided with a heart rate measuring arrangement in which a microprocessor is programmed to perform several functions. In one function, known as the speed mode, the momentary or average speed of the object is calculated. In this solution the speed is, however, calculated in the same way as in conventional pedometers, i.e. the number of steps is obtained from the pedometer and when the step length is fed into the device, the device provides the distance traveled. When the device itself measures the elapsed time or this is fed into the device, the device calculates the speed on the basis of the distance traveled and the elapsed time. In this solution, as usual in pedometers, feeding of the step length is the only significant user-specific information which is used in the calculation of speed. Other user-specific information is not used for measuring the speed but only for forming an appropriate target zone for the user. The publication does not describe any option of teaching. In this prior art method it is impossible to consider the fact that the step length changes as the speed changes. Prior art devices do not contain nor are they provided with a sufficient amount of information on the dependence between the step time or another measurement variable able and the speed.
The object of the invention is to provide a method and a measuring arrangement to eliminate the above-mentioned problems. The objects of the invention are achieved with a method and an arrangement that are characterized by what is disclosed in the independent claims. The dependent claims disclose preferred embodiments of the invention.
The invention is based on the idea that the measuring arrangement is provided with user-specific information for calculating the speed, which forms part of and/or specifies the formula which represents the dependence between. the measurement variable and the speed and is used for calculating the speed. In a more advance version of the invention, this information is teaching information, which is obtained as a result of several actual teaching measurements, in each of which the measurement pair consists of the measurement variable and the speed related thereto, for example. The measurement pair may also consist of the measurement variable and information from which the speed is obtained, i.e. the pair of the measurement variable consists of the time used for a certain known distance and the known distance. In this more advanced version the user of the measuring arrangement teaches the measuring arrangement a formula based on real user-specific measurements. The user creates a formula for the measuring arrangement by means of several, e.g. at least two, pairs of the measurement variable and the speed, i.e. in a way forms a curve representing the measurement variable and the speed, which can also be used for calculating speeds according to other values of the measurement variable in the actual measurements. The second version of the invention employs information which describes the user and specifies the dependence between the measurement variable and the speed set to the device e.g. at the factory, or by a wholesaler or a retailer. This means that the teaching has been carried out already at the factory, for example. In this second version the device is provided with complete formulae, which are kind of curves representing the measurement variable and the speed, and a suitable formula is selected on the basis of the information given by the user, and thus the formula describes the dependence between the measurement variable and the speed of the person according to the user information better than usual.
An advantage of the solution according to the invention is that it provides a rather simple method and a measuring arrangement that are well-suited for industrial mass production and yield accurate measurement results of the object""s speed. User-specific information or user-specific teaching information enables good adaptation to the user""s real situation. A significant advantage of the invention is that it eliminates the disadvantages caused by the fact that the measurement variable, such as the step time, changes as the speed of the object changes.